Thin layer chromatography spotting device

ABSTRACT

A semi-automatic drug-screening spotting device capable of transferring a plurality of specimens simultaneously from disposable capillaries onto a thin layer chromatography (TLC) plate. The device consists of a rectangularly shaped base plate which is provided with a support for vertically mounting a TLC plate. Two side support members are provided with grooves for receiving a clamp plate assembly containing the capillaries. Positioned behind the TLC plate support is a hot air blower for drying the spots. In operation, the clamp assembly is inserted into the side member grooves to tilt the TLC plate backward so that gravity and capillary action force the specimens from the capillaries onto the TLC plate to form a plurality of spots simultaneously.

United States Patent [191 Russell et al.

[ 5] Apr. 30, 1974 THIN LAYER CHROMATOGRAPHY SPO'I'IING DEVICE [73] Assignee: Biochemical Procedures, Inc.,

Hollywood, Calif.

[22] Filed: Oct. 16, 1972 [21] Appl. No.: 297,936

[52] U5. Cl. 23/259, 23/230 B, 23/253 R, 141/130 [51] Int. Cl G0ln 1/18, G0ln 1/14 [58] Field of Search 23/259, 292, 253, 230 B; l4l/l30; 73/425.4 R

[56] References Cited UNITED STATES PATENTS 3,572,552 3/197] Guinn 23/259 X 3,758,275 9/1973 Quame 1. 23/259 Primary ExaminerMorris O. Wolk Assistant Examiner-R. E. Serwin Attorney, Agent, or Firm-David J. Mugford; George A. Mentis; John A. Caruso [57] TRACT A semi-automatic drug-screening spotting device capable of transferring a plurality of specimens simultaneously from disposable capillaries onto a thin layer chromatography (TLC) plate. The device consists of a rectangularly shaped base plate which is provided with a support for vertically mounting a TLC plate. Two side support members are provided with grooves for receiving a clamp plate assembly containing the capillaries. Positioned behind the TLC plate support is a hot air blower for drying the spots. in operation, the clamp assembly is inserted into the side member grooves to tilt the TLC plate backward so that gravity and capillary action force the specimens from the capillaries onto the TLC plate to form a plurality of spots simultaneously.

10 Claims, 6 Drawing Figures asmiss PATENTEBAPR 30 m4 sum 1 OF 2 mmrammmsm 3.807959 SHEET 2 0f 2 THIN LAYER CHROMATOGRAPHYSPOTTING DEVICE BACKGROUND OF THE INVENTION The present invention is not limited to drug screening chromatography, but may be employed in all chromatography procedures. In the preferred embodiment of the invention, however, the apparatus is used in drug screening. I

The detection of drugs using thin layer chromatography generally involves the following steps:

1. Drug extraction from urine;

2. Drug elution and concentration;

3. Sample spotting and development; and

4. Visualization After a sample has been concentrated, it is redissolved and spotted onto a TLC plate.

Thin layer chromatography is presently being used in the detection and identification of drugs from analysis of blood and urine specimens. Various devices are known in the prior art for use in drug detection. For example, U.S. Pat. No. 3,261,208 discloses a series of au- Positioned behind the vertically mounted TLC plate is a hot air blower used for drying the spots.

Specimens and a control are transferred from test tubes into capillaries followed by the insertion of the filled capillaries into the grooves of the bottom plate of the clamp plate assembly. The top plate, fitted with a resilient material such as rubber, polypropylene, polyurethane foam, or the like, is then clamped and the assembly inserted into the guide channels of the TLC plate support. This insertion moves the assembly away from the operator so that the L-shaped support and TLC plate will tilt toward the rear. Gravity and capillary action force the specimens onto the plate when the capillaries are thus contacted with the TLC plate. Hot air passing up the face of the plate dries the specimens. The resulting spots for each specimen are then analyzed according to normal chromatographic procedures.

The improved device of the present invention is durable, well balanced, inexpensive, simple to assemble, easy to handle, requires minimal maintenance and allows for greater uniformity and accuracy. Important features of the invention reside in the vertical mounting tomatic pipettes for extracting and transferring a predetermined amount of liquid to a series of test tubes. U.S. Pat. No. 3,189,413 is drawn to a spot and stripe applicator which employs a series of pipettes and holders. The pipette holders are reciprocated by a cam rod. U.S. Pat. No. 2,956,931 discloses a device for use in spotting a culture with a biological material comprising a backing plate having a series of pins which are dipped into a series of wells. U.S. Pat. No. 3,523,890 is drawn to an apparatus for the separation of a'mixture of a substance which is placed in a cartridge with a solvent. The cartridge is heated and the volatile substance entrained by the solvent vapor leaves the cartridge through a capillary opening onto a sheet of chromatographic material to form a deposit.

It can be appreciated from the above brief description of certain prior art devices that there has been an ever increasing tendency to provide for automatically performing certain procedures which heretofore have been performed manually. Some of theseprior art devices are extremelycomplicated and require considerable care and maintenance in order to insure any degree of accuracy or reproducibility.

By the present invention, a semi-automatic spotting device is provided which is improved, less complicated, free from the disadvantages of prior art devices, simple in design and capable of uniform and low cost spotting. The device of this invention provides spotting capability for a plurality of specimens simultaneously'by transferring the specimensjfrom disposable capillaries onto a thin layer chromatography (.TLC) plate.

The device is comprised of a base plate or support block having a vertically mounted L-shaped tiltable support for a TLC plate. Two side support members are provided with guide channels or grooves for receiving a clamp plate assembly containing a plurality of disposable capillaries. The clamp plate'assembly is comprised of a bottom plate having a plurality of'parallel grooves and a top plate which holds the capillary tubes inplace.

of the TLC plate, the clamp. plate assembly adapted to hold a plurality of capillaries, the use of disposable capillaries, the tiltable design of the L-shaped support which allows for simultaneous and uniform spotting of a plurality of specimens, and the use of hot air to effect speedy and uniform drying.

The above described features, advantages, and objects of the invention as well as others will become more readily apparent from the following description and drawings in which:

FIG. 1 is a perspective view showing the base plate with the tiltable support and the clamp plate assembly;

FIG. 2 is a fragmentary exploded perspective view of the clamp plate assembly;

FIG. 3 is a cross sectional view taken along the line 3-3 of FIG. 1;

FIG. 4 is a side elevational view of the device as shown in FIG. 1;

FIG. 5 is a side elevational view of the device in the tilted position;

FIG. 6 is a tcg) plan view of the device as shown in FIG. 5.

Referring to FIG. 1 it can be seen that the spotting device of the present invention is comprised of a generally rectangular base plate designated by 1, having a rear section 2 and a front section 3. Two supporting legs 9 are located at each end of the base plate. Located toward the front section of the base plate is a vertically mounted L-shaped tiltable support 4 for a thin layer chromatography (TLC) plate 5. Located on each side of and secured to support 4 is a track 4a for receiving plate 5. Mounted onto plate 1 and support 4 are side walls or side support members 6a and 6b which are provided with guide channels 7a and 7b.

Positioned behind support 4 and mounted onto rear section 2 of plate 1 is a hot air blower 8. Also shown in FIG. 1 is a clamp plate assembly 30 comprised of a top plate 12 having a rear section 12a, a bottom plate 13 having a rear section 13a, and a plurality of capillaries 15. Front member 3 of plate 1 has a thickened portion with slots 3a which receive projections 13b of the clamp plate assembly as it is moved toward the rear to engage guide channels 7a and 7b.

In FIG. 2 bottom plate 13 is shown with projection 17 for engagement in opening 16 of top plate 12. A plurality of grooves 14 are for holding disposable capillaries such as shown by 15.

In FIG. 3 resilient material 19 is shown positioned between the top and bottom plates of the clamp plate assembly.

In FIG. 4 the L-shaped vertical support 4 is shown attached to plate 1 by hinge 4b having a stop (not shown) to limit the degree of tilting of vertical support 4 when the clamp plate assembly is engaged into guide channels 7a and 7b. Located on one side of the L-shaped support 4 and mounted to side support member 6a is a latch assembly 20 having a pivot 21 mounted on side support 6a. The lower end 22 of latch 20 engages pin 23 which is secured to base plate 1. Spring 24 is shown having one end secured to pin 25 which is mounted to side support 6a and the other end attached to the upper part 26 of latch 20. Spring 24 normally biases latch 20 in a clockwise direction by engagement of pin 23 so as to lock the L-shaped support 4. As shown in FIG. 4 in the locked position the upper part 26 of latch 20 is in the path of slot 7a of side support member 6a.

In FIG. the device is shown in the tilted position with the clamp plate assembly fully engaged into the channels of the side supports. Rear section 13a of bottom plate 13 contacts upper part 26 of latch 20 to disengage latch 20 from pin 23 thereby tilting the TLC plate as shown. Spring 18 attached to post 18a which is mounted to base plate 1 operates to hold the L- shaped support in the tilted position. Counterweight 40 may be used instead of spring 18 to hold the L-shaped support 4 in the tilted position. As shown the support is tilted at an angle of from 1245". The degree of tilting may be varied as desired depending on the particular conditions involved. Plate 1 is provided with slot 2a which extends the width of base plate 1 and forward of the vertical member of support 4. Toward the forward end of plate 1, baffle plate 2b directs hot air from blower 8 to the front face of the TLC plate 5.

FIG. 6 shows spots 32 which are formed on TLC plate 5 after the clamp plate assembly, loaded with specimen-filled capillaries, has been moved toward the rear to engage guide channels 7a and 7b of the side support members 6a and 6b.

In operation, after the TLC plate 5 is inserted in track 4a and the specimens and control are transferred from test tubes into the capillaries, the filled capillaries are positioned in grooves 14 of the clamp plate assembly 30. The top plate 12 of the clamp plate assembly, provided on its underside with a strip of resilient material 19, is secured to the bottom plate 13 of the assembly by aligning projection 17 in opening 16. Resilient material 19 is used to contact the disposable capillaries 15, which are usually made of glass, and to provide a simple holding effect until the clamp plate assembly is inserted into slots 3a of the base plate.

The clamp plate assembly is then placed on the base plate in the area of front member 3, projections 13b engaging slots 3a. The assembly is then moved along the slots 3a toward the rear section 2, thereby engaging guide channels 7a and 7b. As the clamp plate assembly is moved toward TLC plate 5, section 13a of bottom plate 13 contacts latch 20, disengaging it from pin 23 and tilting the TLC plate. Capillaries move downward and contact the TLC plate simultaneously. Gravity and capillary action force the specimens from the capillaries onto the TLC plate to form spots 23 as shown in FIG. 6. Hot air from blower 8 travels through slot 2a, is deflected by baffle plate 2b onto the front face of TLC plate 5. After the spots are dried, the clamp plate assembly is returned manually to the starting position for disassembly and disposal of the capillaries.

It can be seen from the description of the spotter and its operation that according to the invention a simple yet reliable method is provided for semi-automatically spotting simultaneously a plurality of specimens. The improved spotting device of the invention allows for greater uniformity, low cost per sample analysis, and greater production capability. Use of disposable capillaries eliminates the problem of contamination present in prior art and more complicated devices and methods. Use of hot air to dry the spots also assists in uniformity of results since the temperature and amount of air may be easily controlled, thereby minimizing or eliminating any drifting or distortion of the spots during drymg.

The drug-screening spotter of the present invention is used in screening for such drugs as morphine, barbituates, amphetamines and methadone. However, the device is not limited to use in drug screening but may also be used whereven chromatographic procedures are employed.

What is claimed is:

l. A semi-automatic spotting device capable of spotting a plurality of specimens simultaneously comprising a base plate having a rear section and a front section and having mounted thereon a tiltable support, a thin layer chromatography (TLC) plate attached to said support and a clamp plate assembly adapted to hold a plurality of capillaries and adapted to engage said tiltable support; said support being essentially L-shaped and being comprised of a vertical member, a horizontal member and two side walls, said vertical member having a front face and a rear face, said side walls having guide channels, said clamp plate assembly having a plurality of specimen-containing capillaries and being adapted to engage said guide channels so that, when the clamp plate assembly is inserted into said guide channels and moved toward the TLC plate, said support will tilt at an angle such that the specimens will flow out of the capillaries onto the TLC plate to form substantially simultaneously a plurality of separate and distinct spots.

2. A spotting device according to claim 1 wherein said base plate contains a slot located in said rear section and extending forward of said vertical member of the tiltable support, a baffle plate mounted onto said base plate and positioned in front of said TLC plate, and mounted on said rear section of said base plate a hot air blower; said blower, slot, bafi'le plate and TLC plate being positioned so that hot air will travel through said slot and be deflected onto the front face of the TLC plate to dry the plurality of spots formed on the TLC plate.

3. A spotting device according to claim 1 wherein said tiltable support is adapted to be positioned in a tilted position and in an ultilted position; wherein at least one of said side walls is provided with a latch assembly having a locked and an unlocked position.

4. A spotting device according to claim 3 wherein said latch assembly is comprised of an upper part and a lower part, a pin and a pivot mounted on said side wall and a spring attached to said upper part of the latch assembly, wherein said upper part of said latch assembly is positioned within the guide channel of said side wall so that, when the clamp plate assembly is inserted in the guide channels, the latch assembly will be moved from the locked position to the unlocked position and the tiltable support will be moved from the untilted to the tilted position.

5. A spotting device according to claim 4 wherein said tiltable support has a spring attached at one end to the rear face of said vertical member and at the other end to the rear section of the base plate.

6. A spotting device according to claim 1 wherein said clamp plate assembly is comprised of a top plate having a front and rear section, a bottom plate having a front and rear section and a plurality of grooves for holding capillaries therein.

7. A spotting device according to claim 6 wherein said top plate contains an opening and said bottom plate contains a projection for engagement in said opening.

8. A spotting device according to claim 6 wherein said top plate is provided on its underside with a strip of resilient material.

9. A spotting device being adapted for substantially simultaneously transferring specimens from a plurality of capillaries onto a vertically mounted thin layer chromatography (TLC) plate comprising: (1) a base plate; (2) a TLC support plate mounted to said base plate and adapted to be positioned in a locked, ultilted, vertical position and in an unlocked, tilted position; (3) a clamp plate assembly adapted to hold a plurality of specimenfilled capillaries and adapted to engage said support plate to cause it to move from the locked to the unlocked, tilted position; and (4) a TLC plate attached to said support plate.

10. A spotting device according to claim 9 having a hot air blower mounted to said base plate and wherein said base plate is provided with a slot and baffle plate for deflecting hot air onto the TLC plate. 

2. A spotting device according to claim 1 wherein said base plate contains a slot located in said rear section and extending forward of said vertical member of the tiltable support, a baffle plate mounted onto said base plate and positioned in front of said TLC plate, and mounted on said rear section of said base plate a hot air blower; said blower, slot, baffle plate and TLC plate being positioned so that hot air will travel through said slot and be deflected onto the front face of the TLC plate to dry the plurality of spots formed on the TLC plate.
 3. A spotting device according to claim 1 wherein said tiltable support is adapted to be positioned in a tilted position and in an ultilted position; wherein at least one of said side walls is provided with a latch assembly having a locked and an unlocked position.
 4. A spotting device according to claim 3 wherein said latch assembly is comprised of an upper part and a lower part, a pin and a pivot mounted on said side wall and a spring attached to said upper part of the latch assembly, wherein said upper part of said latch assembly is positioned within the guide channel of said side wall so that, when the clamp plate assembly is inserted in the guide channels, the latch assembly will be moved from the locked position to the unlocked position and the tiltable support will be moved from the untilted to the tilted position.
 5. A spotting device according to claim 4 wherein said tiltable support has a spring attached at one end to the rear face of said vertical member and at the other end to the rear section of the base plate.
 6. A spotting device according to claim 1 wherein said clamp plate assembly is comprised of a top plate having a front and rear section, a bottom plate having a front and rear section and a plurality of grooves for holding capillaries therein.
 7. A spotting device according to claim 6 wherein said top plate contains an opening and said bottom plate contains a projection for engagement in said opening.
 8. A spotting device according to claim 6 wherein said top plate is provided on its underside with a strip of resilient material.
 9. A spotting device being adapted for substantially simultaneously transferring specimens from a plurality of capillaries onto a vertically mounted thin layer chromatography (TLC) plate comprising: (1) a base plate; (2) a TLC support plate mounted to said base plate and adapted to be positioned in a locked, ultilted, vertical position and in an unlocked, tilted position; (3) a clamp plate assembly adapted to hold a plurality of specimen-filled capillaries and adapted to engage said support plate to cause it to move from the locked to the unlocked, tilted position; and (4) a TLC plate attached to said support plate.
 10. A spotting device according to claim 9 having a hot air blower mounted to said base plate and wherein said base plate is provided with a slot and baffle plate for deflecting hot air onto the TLC plate. 